Economic Opportunities for Reducing Net Global Warming Potential in Irrigated Cropping Systems in Northeastern Colorado

A cropping systems field study initiated in 1999 was used in this analysis to evaluate the economic feasibility of achieving reductions in net global warming potential through changes in cropping system management. Crop yield and management information collected from 2000-2005 were used to estimate the profitability of a conventional-till continuous corn rotation (CT-CC), a no-till continuous corn rotation (NT-CC), and a no-till corn-soybean or dry bean (NT-CB) rotation over a range of nitrogen fertilizer rates (0 to 246 kg N ha^-1). Management information was also used to estimate greenhouse gas emissions from production activities, and was combined with soil organic carbon and trace gas flux measurements to determine the net global warming potential for each cropping system. At economic optimum N fertilizer rates, global warming potential was lowest for NT-CC, followed by NT-CB, and highest for CT-CC. Using 2007 input costs and crop prices, net returns were highest for NT-CB, followed by CT-CC and NT-CC. The results show an opportunity for both increasing economic returns and reducing net global warming potential by changing from CT-CC to NT-CB. Further reductions in net global warming potential could be achieved through adoption of NT-CC, however with a slight reduction in net returns at 2007 price levels. If producers received payments based on net global warming potential relative to CT-CC, a payment of $2.40 Mg^-1 C-equivalent emissions would be sufficient to offset reductions in net returns for NT-CC in switching from CT-CC.